Analysis of what factors affect the accuracy of water quality analyzer measurement

The water quality analyzer is a rare water quality monitoring instrument that can accurately determine whether the water quality is polluted. But at the same time, there are many unfavorable factors that want to affect the monitoring data of the water quality analyzer, such as the fully enclosed system, the accuracy of sampling, the speed of magnetic mixing, etc., but in practice, if the water quality online monitor can be used in a targeted and correct manner, It can still effectively improve the accuracy of instrument monitoring, make its data representative, and at the same time, it can also complete the long-term effective and stable operation of the water quality analyzer system.

1. The system is fully enclosed

The connection of the Karl Fischer reagent liquid path must be fastened, from the reagent bottle to the metering pump to the reaction tank, otherwise, reagent leakage will directly affect the test results. Another problem with its non-sealing is that the Karl Fischer reagent absorbs air moisture during the test, which will cause the end of the titration to be delayed.

2. The precise problem of sampling

When calibrating the Karl Fischer reagent, you need to take 10mg of water. Try to use a 10ul sampler. This is not only accurate and fast but also prevents the adhesion of water droplets. Similarly, the use of methanol reagents and ethyl esters also have similar problems. After the handling is completed, attention should be paid to shorten the time when the reaction cell is opened as much as possible.

3. Magnetic mixing speed adjustment

In the reverberation cell, because the titration reagent is in the part when it is added, it is not in the same place as the electrode, so the mixing speed is so fast that no turbulence is formed so that it can reach the end soon.

4. The system is as tight as possible

The manual moisture analyzer needs to add a U-shaped tube filled with desiccant to the top of the suction bulb pipe and the glass burette to reduce the disturbance of air moisture to the test results. In an environment where the relative humidity of the air is greater than 70%, the moisture test should not be arranged as much as possible.

5. The titration speed setting should be fast and then slow. The titration is fast at first to shorten the experiment time as much as possible, and the strain is slow towards the end, which can improve the meter measurement.

6. The water quality analyzer should be far away from the strong magnetic field to prevent the electrons from appearing to be bounced and abnormal during operation. For manual moisture analyzers, it is necessary to use a glass automatic burette to measure Karl Fischer reagent and methanol solvent, and the glass burette itself needs to be connected to the outside due to the equilibrium pressure.

7. When adjusting the titration speed of the burette, adjust it to 1 drop/sec. Too fast a titration speed will result in a larger delay error when the end is reached; while a too slow titration speed will prolong the test process, and the above-mentioned disturbances will easily lead to delays in reaching the end.

8. After the experiment on the same day, the Karl Fischer reagent in the system must be drained, and then cleaned with methanol. Never clean the system with water. Because it is not easy to volatilize, it will cause the Karl-Fischer reagent in the next experiment. The Fischer reagent is not calibrated correctly.